Electro-optical device, method of manufacturing electro-optical device, electro-optical unit, and electronic apparatus

ABSTRACT

In an electro-optical device, light is incident on a mirror by penetrating a cover, and the light reflected by the mirror is emitted by penetrating the cover. Here, the cover includes a first light-transmitting plate and a second light-transmitting plate facing the first light-transmitting plate, and a gap which is open toward both sides in a first direction is provided between the first light-transmitting plate and the second light-transmitting plate due to a spacer.

This is a Continuation of U.S. application Ser. No. 15/017,960 filedFeb. 8, 2016, which claims the benefit of Japanese Application No.2015-065934 filed Mar. 27, 2015. The disclosures of the priorapplications are hereby incorporated by reference herein in theirentireties.

BACKGROUND

1. Technical Field

The present invention relates to an electro-optical device provided witha mirror, a method of manufacturing the electro-optical device, anelectro-optical unit, and an electronic apparatus.

2. Related Art

As an electronic apparatus, for example, a projection type displaydevice or the like is known which displays an image on a screen bymodulating light emitted from a light source by a plurality of mirrors(micromirrors) of an electro-optical device called a digital mirrordevice (DMD) and then enlarging and projecting the modulated light by aprojection optical system. The electro-optical device which is used insuch a projection type display device or the like is provided with anelement substrate 1 in which a mirror 50 is provided on a one-sidesurface 1 s, a frame section 61 bonded to the one-side surface 1 s sideof the element substrate 1 so as to surround the mirror 50 when viewedin a plan view, and a plate-shaped light-transmitting cover 71 supportedon an end portion on the side opposite to the element substrate 1, ofthe frame section 61, as shown in FIG. 13, for example. Further, theelectro-optical device has, for example, a support substrate 90 in whicha concave substrate mounting portion 93 surrounded by a side wall 92 isformed, and the element substrate 1 is fixed to a bottom portion of thesubstrate mounting portion 93 by an adhesive 97 and then sealed bysealing resin 98 provided in the substrate mounting portion 93.

In the electro-optical device configured in this manner, light isincident on the mirror 50 by penetrating the light-transmitting cover71, and the light reflected by the mirror 50 is emitted by penetratingthe light-transmitting cover 71. At this time, the temperature of theelement substrate 1 or the like rises due to the light illuminated tothe light-transmitting cover 71 or the one-side surface is of theelement substrate 1. Such a rise in temperature causes a malfunction ora decrease in life of the electro-optical device, and therefore, it isnot preferable.

On the other hand, as a method of increasing the heat dissipation of adevice mounted on the support substrate 90, a technique of widening thecontact area between the device and the sealing resin is proposed (referto U.S. Pat. No. 7,898,724 B2). For example, as shown in FIG. 13, aconfiguration is made in which the surface of the sealing resin 98 is incontact with the light-transmitting cover 71 at a position higher than aposition where the surface of the sealing resin 98 is in contact withthe side wall 92 of the support substrate 90. According to such aconfiguration, it is possible to increase heat transfer efficiency fromthe light-transmitting cover 71 to the sealing resin 98.

However, according to the configuration shown in FIG. 13, even if theheat transfer efficiency from the light-transmitting cover 71 to thesealing resin 98 is increased, since the heat transfer efficiency of thesealing resin 98 itself is low, there is a problem in that it is notpossible to sufficiently suppress an rise in the temperature of theelement substrate 1.

SUMMARY

An advantage of some aspects of the invention is to provide anelectro-optical device in which it is possible to suppress a rise in thetemperature of an element substrate or the like which is provided with amirror, a method of manufacturing the electro-optical device, anelectro-optical unit, and an electronic apparatus.

An electro-optical device according to an aspect of the inventionincludes: an element substrate on which a mirror and a drive elementwhich drives the mirror are provided on a first surface side; and acover which is provided on the first surface side and disposed such thatthe mirror is located between the element substrate and the cover,wherein the cover includes a first light-transmitting plate having alight-transmitting property, a second light-transmitting plate having alight-transmitting property and disposed such that the firstlight-transmitting plate is located between the mirror and the secondlight-transmitting plate, and a spacer which is interposed between thefirst light-transmitting plate and the second light-transmitting plateand provided with a gap which is open toward both sides in a firstdirection intersecting a thickness direction in which the firstlight-transmitting plate and the second light-transmitting plate faceeach other, between the first light-transmitting plate and the secondlight-transmitting plate.

In the electro-optical device according to the aspect of the invention,light is incident on the mirror by penetrating the cover, and the lightreflected by the mirror is emitted by penetrating the cover. At thistime, the temperature of the element substrate or the like tries to risedue to the light illuminated to the cover or a one-side surface of theelement substrate. Here, in the cover, the gap which is open toward bothsides in the first direction is provided between the firstlight-transmitting plate and the second light-transmitting plate due tothe spacer. For this reason, by passing a fluid such as air through thegap, it is possible to increase heat dissipation of the cover or thelike. Therefore, even when the temperature of the element substrate orthe like tries to rise due to the illuminated light or the like, it ispossible to suppress a rise in the temperature of the element substrateor the like. For this reason, it is possible to suppress a malfunctionor a decrease in life of the electro-optical device.

In the aspect of the invention, it is preferable that the spacer isconfigured integrally with the second light-transmitting plate.According to such a configuration, it is possible to improve theefficiency of assembly work of the electro-optical device.

The aspect of the invention may adopt a configuration in which thespacer includes a first spacer which extends in the first direction, anda second spacer which extends in the first direction at a positionseparated from the first spacer in a second direction intersecting thethickness direction and the first direction with respect to the firstspacer, and the gap is open toward both sides in the first directionbetween the first spacer and the second spacer. According to such aconfiguration, when a fluid such as air passes through the gap, leakageof the fluid in the second direction does not occur, and therefore, flowvelocity in the gap is fast. Therefore, it is possible to increase heatdissipation in the cover.

In the aspect of the invention, it is preferable that the first spacerand the second spacer extend in the first direction along end portionswhich are located on both sides in the second direction in the firstlight-transmitting plate. According to such a configuration, when afluid such as air passes through the gap, it is possible to widen thecontact area between the first light-transmitting plate and the fluid.Therefore, it is possible to increase heat dissipation in the cover.

In the electro-optical device according to the aspect of the invention,it is preferable that the electro-optical device further includes ablower which supplies air toward the gap from one side in the firstdirection with respect to the gap. Further, in the aspect of theinvention, an electro-optical unit in which the electro-optical deviceand the blower are supported on a holder may be configured. According tosuch a configuration, it is possible to reliably pass air through thegap between the first light-transmitting plate and the secondlight-transmitting plate, and therefore, it is possible to increase heatdissipation in the cover.

In this case, it is preferable that the electro-optical device furtherincludes a support substrate on which the element substrate is mountedand that the support substrate is provided with a bottom plate portionon which the element substrate is mounted, a first side wall whichprotrudes from the bottom plate portion to a side on which the elementsubstrate is mounted, on the one side in the first direction withrespect to the element substrate, and a second side wall which protrudesfrom the bottom plate portion to the side on which the element substrateis mounted, on the other side in the first direction with respect to theelement substrate, and the first side wall has a higher height from thebottom plate portion than the second side wall. According to such aconfiguration, an air flow having gotten over the first side wall wrapsaround to the inside of the first side wall and then easily flows towardthe gap. Therefore, it is possible to increase heat dissipation in thecover.

An electro-optical device according to another aspect of the inventionincludes: an element substrate on which a mirror and a drive elementwhich drives the mirror are provided on a first surface side; and acover which is provided on the first surface side and disposed such thatthe mirror is located between the element substrate and the cover,wherein the cover includes a first light-transmitting plate having alight-transmitting property, a second light-transmitting plate having alight-transmitting property and disposed such that the firstlight-transmitting plate is located between the mirror and the secondlight-transmitting plate, and a spacer which is located between thefirst light-transmitting plate and the second light-transmitting plate,has a first spacer extending in a first direction, and a second spacerextending in the first direction at a position separated from the firstspacer in a second direction intersecting the first direction withrespect to the first spacer, and is provided to avoid at least a portionof a first end portion of the first light-transmitting plate in thefirst direction and avoid at least a portion of a second end portionfacing the first end portion of the first light-transmitting plate inthe first direction.

In the electro-optical device according to the aspect of the invention,light is incident on the mirror by penetrating the cover, and the lightreflected by the mirror is emitted by penetrating the cover. At thistime, the temperature of the element substrate or the like tries to risedue to the light illuminated to the cover or a one-side surface of theelement substrate. Here, in the cover, the gap which is open toward bothsides in the first direction is provided between the firstlight-transmitting plate and the second light-transmitting plate due tothe spacer. For this reason, by passing a fluid such as air through thegap, it is possible to increase heat dissipation of the cover or thelike. Therefore, even when the temperature of the element substrate orthe like tries to rise due to the illuminated light or the like, it ispossible to suppress a rise in the temperature of the element substrateor the like. For this reason, it is possible to suppress a malfunctionor a decrease in life of the electro-optical device.

A method of manufacturing an electro-optical device according to stillanother aspect of the invention includes: preparing a first wafer onwhich a mirror and a drive element which drives the mirror are providedon a first surface side; forming a laminated wafer in which a secondwafer having a light-transmitting property and a third wafer having alight-transmitting property are bonded to overlap each other through aspacer and a concave portion is formed in a second surface on a sideopposite to a surface facing the third wafer, of the second wafer;bonding the first surface of the first wafer and the second surface ofthe second wafer to each other in an overlap state such that the mirrorand the drive element overlap the concave portion when viewed in a planview; and dividing a portion with the mirror and the drive elementprovided therein from the first wafer and the laminated wafer.

In the aspect of the invention, it is preferable that in the formationof the laminated wafer, after the spacer is formed integrally with, forexample, the third wafer, a fourth wafer having a light-transmittingproperty, which configures a third surface side on a side opposite tothe second surface of the second wafer, is bonded to overlap a side onwhich the spacer is formed, of the third wafer, and a fifth wafer havinga light-transmitting property, which configures the first surface sideof the second wafer, is bonded to overlap the fourth wafer, and athrough-hole for configuring the concave portion is formed in the fifthwafer.

The electro-optical device or the electro-optical unit to which theinvention is applied can be used in a variety of electronic apparatuses,and in this case, an electronic apparatus is provided with a lightsource unit which irradiates the mirror with light source light.Further, in a case where as an electronic apparatus, a projection typedisplay device is configured, the electronic apparatus is furtherprovided with a projection optical system which projects light modulatedby the mirror.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic diagram showing an optical system of a projectiontype display device as an electronic apparatus to which the invention isapplied.

FIGS. 2A and 2B are explanatory diagrams schematically showing a basicconfiguration of an electro-optical device to which the invention isapplied.

FIGS. 3A and 3B are explanatory diagrams schematically showing a basicconfiguration of the electro-optical device to which the invention isapplied.

FIG. 4 is a plan view of an electro-optical device according toEmbodiment 1 of the invention.

FIGS. 5A and 5B are cross-sectional views of the electro-optical deviceaccording to Embodiment 1 of the invention.

FIGS. 6A to 6D are process cross-sectional views showing a method ofmanufacturing the electro-optical device according to Embodiment 1 ofthe invention.

FIGS. 7A and 7B are process diagrams showing a method of manufacturing afirst wafer or the like which is used in the manufacturing of theelectro-optical device according to Embodiment 1 of the invention.

FIGS. 8A to 8F are process diagrams showing a method of manufacturing alaminated wafer or the like which is used in the manufacturing of theelectro-optical device according to Embodiment 1 of the invention.

FIGS. 9A to 9C are process cross-sectional views showing a process ofsealing an element substrate by a support substrate and sealing resin inthe manufacturing process of the electro-optical device according toEmbodiment 1 of the invention.

FIG. 10 is a plan view of an electro-optical device according toEmbodiment 2 of the invention.

FIGS. 11A and 11B are cross-sectional views of the electro-opticaldevice according to Embodiment 2 of the invention.

FIG. 12 is a cross-sectional view of an electro-optical device accordingto Embodiment 3 of the invention.

FIG. 13 is a cross-sectional view of an electro-optical device accordingto a reference example of the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments of the invention will be described with reference to thedrawings. In addition, in the following description, as an electronicapparatus to which the invention is applied, a projection type displaydevice will be described. Further, in the drawings which are referred toin the following description, in order to make each layer or each memberhave a size of the degree recognizable on the drawings, a reduced scaleis varied for each layer or each member. The number of mirrors or thelike shown in the drawings is set such that the mirror or the like has asize of the degree recognizable on the drawings. However, more mirrorsor the like than the number shown in the drawings may be provided. Inaddition, in the following embodiments, it is assumed that a case ofbeing described, for example, as “being disposed on the first surfaceside” may include a case of being disposed so as to be in contact withthe first surface, a case of being disposed on the first surface throughthe other component, or a case of being partially disposed so as to bein contact with the first surface and being partially disposed throughthe other component.

EMBODIMENT 1 Projection Type Display Device as Electronic Apparatus

FIG. 1 is a schematic diagram showing an optical system of a projectiontype display device as an electronic apparatus to which the invention isapplied. A projection type display device 1000 shown in FIG. 1 has alight source unit 1002, an electro-optical device 100 which modulateslight emitted from the light source unit 1002 in accordance with imageinformation, and a projection optical system 1004 which projects thelight modulated in the electro-optical device 100 to a projected object1100 such as a screen as a projection image. The light source unit 1002is provided with a light source 1020 and a color filter 1030. The lightsource 1020 emits white light, the color filter 1030 emits light of eachcolor in accordance with rotation, and the electro-optical device 100modulates incident light at a timing synchronized with the rotation ofthe color filter 1030. In addition, instead of the color filter 1030, aphosphor substrate which converts the light emitted from the lightsource 1020 into light of each color may be used. Further, the lightsource unit 1002 and the electro-optical device 100 may be provided foreach light of each color.

Basic Configuration of Electro-Optical Device 100

FIGS. 2A and 2B are explanatory diagrams schematically showing a basicconfiguration of the electro-optical device 100 to which the inventionis applied, and FIGS. 2A and 2B respectively are an explanatory diagramshowing a main section of the electro-optical device 100 and an explodedperspective view of the main section of the electro-optical device 100.FIGS. 3A and 3B are explanatory diagrams showing a line A-A′cross-section in the main section of the electro-optical device 100 towhich the invention is applied, and FIGS. 3A and 3B respectively are anexplanatory diagram schematically showing a state where a mirror istilted to one side and an explanatory diagram schematically showing astate where the mirror is tilted to the other side.

As shown in FIGS. 2A to 3B, in the electro-optical device 100, aplurality of mirrors 50 are disposed on the one-side surface is (firstsurface) side of an element substrate 1 in a matrix form, and themirrors 50 are separated from the element substrate 1. The elementsubstrate 1 is, for example, a silicon substrate. Each of the mirrors 50is, for example, a micromirror having a plane size in which the lengthof one side is in a range of 10 μm to 30 μm, for example. The mirrors 50are disposed with an array in a range of 800×600 to 1028×1024, forexample, and one mirror 50 corresponds to one pixel of an image.

The surface of the mirror 50 is a reflective surface made of areflective metal film such as aluminum, for example. The electro-opticaldevice 100 is provided with a first floor portion 100 a which includes asubstrate-side bias electrode 11, substrate-side address electrodes 12and 13, and the like formed on the one-side surface is of the elementsubstrate 1, a second floor portion 100 b which includes elevatedaddress electrodes 32 and 33 and a hinge 35, and a third floor portion100 c which includes the mirrors 50. In the first floor portion 100 a,an addressing circuit 14 is formed on the element substrate 1. Theaddressing circuit 14 is provided with a memory cell for selectivelycontrolling an operation of each mirror 50, wiring 15 of a word line anda bit line, and the like, and has a circuit configuration similar to arandom access memory (RAM) provided with a CMOS circuit 16.

The second floor portion 100 b includes the elevated address electrodes32 and 33, the hinge 35, and a mirror post 51. The elevated addresselectrodes 32 and 33 electrically conduct to the substrate-side addresselectrodes 12 and 13 through electrode posts 321 and 331 and aresupported by the substrate-side address electrodes 12 and 13. Hinge arms36 and 37 extend from both ends of the hinge 35. The hinge arms 36 and37 electrically conduct to the substrate-side bias electrode 11 througharm posts 39 and are supported on the substrate-side bias electrode 11.The mirror 50 electrically conduct to the hinge 35 through the mirrorpost 51 and is supported by the hinge 35. Therefore, the mirror 50electrically conducts to the substrate-side bias electrode 11 throughthe mirror post 51, the hinge 35, the hinge arms 36 and 37, the armposts 39 and is applied with bias voltage from the substrate-side biaselectrode 11. In addition, stoppers 361, 362, 371, and 372 which preventcontact between the mirror 50 and the elevated address electrodes 32 and33 by coming into contact with the mirror 50 when the mirror 50 istilted are formed at the tips of the hinge arms 36 and 37.

The elevated address electrodes 32 and 33 configure a drive element 30which generates an electrostatic force between itself and the mirror 50,thereby driving the mirror 50 so as to tilt. Further, there is a casewhere the substrate-side address electrodes 12 and 13 are alsoconfigured so as to generate an electrostatic force between themselvesand the mirror 50, thereby driving the mirror 50 so as to tilt, and inthis case, the drive element 30 is configured with the elevated addresselectrodes 32 and 33 and the substrate-side address electrodes 12 and13. The hinge 35 is twisted when drive voltage is applied to theelevated address electrodes 32 and 33 and thus the mirror 50 is tiltedso as to be attracted to the elevated address electrode 32 or theelevated address electrode 33, as shown in FIGS. 3A and 3B, and exerts aforce which returns the mirror 50 to a posture parallel to the elementsubstrate 1, when the application of the drive voltage to the elevatedaddress electrodes 32 and 33 is stopped and thus a suction force to themirror 50 disappears.

In the electro-optical device 100, for example, as shown in FIG. 3A, ifthe mirror 50 is tilted to the side of the elevated address electrode 32on one side, an ON state is created where light emitted from the lightsource unit 1002 is reflected toward the projection optical system 1004by the mirror 50. In contrast, as shown in FIG. 3B, if the mirror 50 istilted to the side of the elevated address electrode 33 on the otherside, an OFF state is created where light emitted from the light sourceunit 1002 is reflected toward a light absorbing device 1005 by themirror 50, and in such an OFF state, light is not reflected toward theprojection optical system 1004. Such driving is performed at each of theplurality of mirrors 50, and as a result, the light emitted from thelight source unit 1002 is modulated into image light by the plurality ofmirrors 50 and projected from the projection optical system 1004,thereby displaying an image.

In addition, there is also a case where a flat plate-shaped yoke facingthe substrate-side address electrodes 12 and 13 is provided integrallywith the hinge 35 and the mirror 50 is driven by using even anelectrostatic force which acts between the substrate-side addresselectrodes 12 and 13 and the yoke, in addition to an electrostatic forcewhich is generated between the elevated address electrodes 32 and 33 andthe mirror 50.

Overall Structure of Electro-Optical Device 100

FIG. 4 is a plan view of the electro-optical device 100 according toEmbodiment 1 of the invention. FIGS. 5A and 5B are cross-sectional viewsof the electro-optical device 100 according to Embodiment 1 of theinvention, in which FIG. 5A is a cross-sectional view taken along lineA1-A1′ of FIG. 4 and FIG. 5B is a cross-sectional view taken along lineB1-B1′ of FIG. 4.

As shown in FIGS. 4, 5A, and 5B, in the electro-optical device 100 ofthis embodiment, the one-side surface is of the element substrate 1 onwhich the plurality of mirrors 50 and the like described with referenceto FIGS. 2A to 3B are formed is sealed by a frame section 61 surroundingthe mirrors 50, and a flat plate-shaped cover 75. Further, the framesection 61 is formed so as to surround the mirrors 50 when viewed in aplan view (for example, a plan view when viewed from the one-sidesurface is side of the element substrate 1). Further, theelectro-optical device 100 is provided with a support substrate 90 madeof a ceramic substrate, and the element substrate 1 is fixed to aconcave substrate mounting portion 93 of the support substrate 90 andthen sealed by sealing resin 98 such as epoxy resin. In the supportsubstrate 90, the substrate mounting portion 93 is made to be a bottomedconcave portion surrounded by a side wall 92, and the element substrate1 is fixed to a bottom plate portion 91 of the support substrate 90 byan adhesive 97. In this embodiment, as the support substrate 90, analuminum nitride-based substrate having high thermal conductivity isused. As the adhesive 97, a metal-based adhesive having high thermalconductivity, such as silver paste, is used.

Here, an end portion 61 e on the side facing the element substrate 1, ofthe frame section 61, is bonded to the one-side surface is of theelement substrate 1. The cover 75 is bonded to an end portion 61 f onthe side opposite to the end portion 61 e of the frame section 61 andsupported on the end portion 61 f. In this state, the cover 75 faces thesurfaces of the mirrors 50 at a position separated by a predetermineddistance from the mirrors 50. In other words, the cover 75 is providedon the one-side surface is side of the element substrate 1 and disposedsuch that the mirrors 50 are located between the element substrate 1 andthe cover 75. Therefore, light is incident on the mirrors 50 bypenetrating the cover 75, and thereafter, the light reflected by themirrors 50 is emitted by penetrating the cover 75. In this embodiment,the cover 75 is made of glass. The frame section 61 may be made of anyof glass, silicon, metal, ceramic, and resin, and in this embodiment, asthe frame section 61, a glass substrate or a silicon substrate is used.

A plurality of terminals 17 are formed at end portions (outside theframe section 61) which do not overlap the mirrors 50, in the one-sidesurface is of the element substrate 1. In this embodiment, the terminals17 are disposed in two rows so as to sandwich the mirrors 50therebetween. Some of the plurality of terminals 17 are electricallyconnected to the elevated address electrodes 32 and 33 (the driveelement 30) through the addressing circuit 14 or the substrate-sideaddress electrodes 12 and 13 described with reference to FIGS. 2A to 3B.Some other terminals of the plurality of terminals 17 are electricallyconnected to the mirrors 50 through the addressing circuit 14, thesubstrate-side bias electrode 11, and the hinge 35 described withreference to FIGS. 2A to 3B. Some still other terminals of the pluralityof terminals 17 are electrically connected to a drive circuit or thelike provided in front of the addressing circuit 14 described withreference to FIGS. 2A to 3B.

Here, the terminal 17 is in an open state on the side opposite to theelement substrate 1, and therefore, the terminal 17 is electricallyconnected to an internal electrode 94 formed on an inner surface 91 s onthe element substrate 1 side of the bottom plate portion 91 of thesupport substrate 90, by a wire 99 for wire bonding. The bottom plateportion 91 of the support substrate 90 is made to be a multilayer wiringsubstrate, and the internal electrode 94 electrically conduct to anexternal electrode 96 formed on an outer surface 91 t on the sideopposite to the element substrate 1, of the bottom plate portion 91,through a through-hole formed in the bottom plate portion 91, or amultilayer wiring section 95 composed of wiring.

The sealing resin 98 is provided inside (a concave portion) of the sidewall 92 of the support substrate 90. The sealing resin 98 covers thecircumferences of the element substrate 1 and the frame section 61 andalso covers the side surface of the cover 75 to the middle in athickness direction.

Configurations of Cover 75 and the Like

In the electro-optical device 100 of this embodiment, all of the supportsubstrate 90, the element substrate 1, and the cover 75 have arectangular planar shape. Therefore, in the following description, adescription will be made regarding a direction in which a long side in arectangular planar shape extends, as a first direction X1, and regardinga direction in which a short side extends, as a second direction Y1.

In the electro-optical device 100 of this embodiment, the cover 75 has afirst light-transmitting plate 76 which faces the mirrors 50 from theside opposite to the element substrate 1, and a secondlight-transmitting plate 77 which faces the first light-transmittingplate 76 on the side opposite to the mirrors 50. Further, the secondlight-transmitting plate 77 is disposed such that the firstlight-transmitting plate 76 is located between the mirrors 50 and thesecond light-transmitting plate 77. Further, the firstlight-transmitting plate 76 has a light-transmitting property, and thesecond light-transmitting plate 77 has a light-transmitting property.Further, the cover 75 has a spacer 78 between the firstlight-transmitting plate 76 and the second light-transmitting plate 77.The spacer 78 is provided at a position which does not overlap themirrors 50 when viewed in a plan view (for example, a plan view when theelement substrate 1 is viewed from the one-side surface is side), and agap 79 is configured between the first light-transmitting plate 76 andthe second light-transmitting plate 77 due to the spacer 78. Further,the sealing resin 98 is provided such that the surface of the sealingresin 98 is at a height position which does not block the gap 79.

In this embodiment, the spacer 78 is composed of a convex portion formedintegrally with the second light-transmitting plate 77. Therefore, thefirst light-transmitting plate 76 is bonded to an end portion on thefirst light-transmitting plate 76 side of the spacer 78, thereby beinglaminated with the second light-transmitting plate 77.

The gap 79 is open toward both sides in the first direction X1intersecting a thickness direction Z in which the firstlight-transmitting plate 76 and the second light-transmitting plate 77face each other. More specifically, the spacer 78 includes a firstspacer 781 extending in the first direction X1, and a second spacer 782extending in the first direction X1 at a position separated from thefirst spacer 781 in the second direction Y1 with respect to the firstspacer 781. For this reason, the gap 79 is open toward both sides in thefirst direction X1 between the first spacer 781 and the second spacer782. Further, the first spacer 781 and the second spacer 782 areprovided so as to avoid at least a portion of an end portion (a firstend portion) on one side in the first direction X1 of the firstlight-transmitting plate 76 and avoid at least a portion of an endportion (a second end portion) on the other side in the first directionX1 of the first light-transmitting plate 76.

The first spacer 781 and the second spacer 782 respectively extend inthe first direction X1 along end portions 761 and 762 which are locatedon both sides in the second direction Y1 (both sides in a short sidedirection) in the first light-transmitting plate 76. In this embodiment,the first light-transmitting plate 76 and the second light-transmittingplate 77 are portions cut at the same time from a wafer in amanufacturing process which will be described later. For this reason,the first light-transmitting plate 76 and the second light-transmittingplate 77 overlap each other to have the same size and the same shape.Therefore, the first spacer 781 and the second spacer 782 extend in thefirst direction X1 along end portions 771 and 772 which are located onboth sides in the second direction Y1 (both side in the short sidedirection) in the second light-transmitting plate 77.

As shown in FIG. 4, in the electro-optical device 100 of thisembodiment, a blower 190 composed of a blast fan or the like whichsupplies air toward the gap 79 from one side X1 a in the first directionX1 is provided outside the support substrate 90, and the supportsubstrate 90 and the blower 190 are held by a holder 180. For thisreason, an air flow supplied toward the gap 79 from the blower 190 getsover the side wall 92 of the support substrate 90 and flows from the oneside X1 a in the first direction X1 into the gap 79, as shown by anarrow C in FIG. 5B, and flows out from the other side X1 b in the firstdirection X1 through the gap 79.

Main Effect of this Embodiment

As described above, in the electro-optical device 100 of thisembodiment, light is incident on the mirrors 50 by penetrating the cover75, and the light reflected by the mirrors 50 is emitted by penetratingthe cover 75. At this time, the temperature of the element substrate 1or the cover 75 tries to rise due to the light illuminated to the cover75 or the one-side surface is of the element substrate 1. Here, in thecover 75, the gap 79 which is open toward both sides in the firstdirection X1 is provided between the first light-transmitting plate 76and the second light-transmitting plate 77 due to the spacer 78. Forthis reason, by passing a fluid such as air through the gap 79, it ispossible to increase heat dissipation in the cover 75. For example, whenan air flow supplied toward the gap 79 from the blower 190 gets over theside wall 92 of the support substrate 90 and flows from the one side X1a in the first direction X1 into the gap 79, as shown by an arrow C inFIG. 5B, and then passes through the gap 79, the air flow takes heatfrom the cover 75. Therefore, even when the temperature of the elementsubstrate 1 or the like tries to rise due to the illuminated light orthe like, it is possible to suppress a rise in the temperature of theelement substrate 1 or the like. For this reason, it is possible tosuppress a malfunction or a decrease in life of the electro-opticaldevice 100.

Further, the spacer 78 is configured integrally with the secondlight-transmitting plate 77, and therefore, it is possible to improvethe efficiency of assembly work of the electro-optical device 100.

Further, the spacer 78 is composed of the first spacer 781 and thesecond spacer 782 which extend in the first direction X1 at positionsseparated from each other in the second direction Y1. For this reason,when an air flow passes through the gap 79, the air flow does not leakin the second direction Y1 from the gap 79. Therefore, the flow velocityof the air flow in the gap 79 is fast, and therefore, it is possible toincrease heat dissipation in the cover 75.

Further, the first spacer 781 and the second spacer 782 extend in thefirst direction X1 along the end portions 761 and 762 which are locatedon both sides in the second direction Y1 in the first light-transmittingplate 76. For this reason, the plane area of the gap 79 is wide, andtherefore, when an air flow passes through the gap 79, it is possible towiden the contact area between the cover 75 and the air flow. For thisreason, it is possible to increase heat dissipation in the cover 75.

Further, the electro-optical device 100 is provided with the blower 190which supplies air toward the gap 79 from the one side X1 a in the firstdirection X1 with respect to the gap 79. For this reason, it is possibleto reliably pass an air flow through the gap 79 between the firstlight-transmitting plate 76 and the second light-transmitting plate 77,and therefore, it is possible to increase heat dissipation in the cover75.

Further, the gap 79 is open toward a longitudinal direction of the cover75. For this reason, flow velocity when an air flow passes through thegap 79 is fast, and therefore, it is possible to increase heatdissipation in the cover 75.

Method of Manufacturing Electro-Optical Device 100

A method of manufacturing the electro-optical device 100 according toEmbodiment 1 of the invention will be described with reference to FIGS.6A to 9C. FIGS. 6A to 6D are process cross-sectional views showing amethod of manufacturing the electro-optical device 100 according toEmbodiment 1 of the invention. FIGS. 7A and 7B are process diagramsshowing a method of manufacturing a first wafer or the like which isused in the manufacturing of the electro-optical device 100 according toEmbodiment 1 of the invention. FIGS. 8A to 8F are process diagramsshowing a method of manufacturing a laminated wafer or the like which isused in the manufacturing of the electro-optical device 100 according toEmbodiment 1 of the invention. FIGS. 9A to 9C are processcross-sectional views showing a process of sealing the element substrate1 by the support substrate 90 and the sealing resin 98 in themanufacturing process of the electro-optical device 100 according toEmbodiment 1 of the invention. In addition, in FIGS. 7A, 7B and 8A to8F, a plan view of a wafer in each process is shown and a cut end viewis shown below the plan view. Further, in FIG. 7B, illustration of themirror and the like is omitted, and in FIGS. 8A to 8F and the like,illustration of the drive element 30 and the like is omitted, and thenumber of mirrors 50 is reduced and thus three mirrors 50 are shown asbeing formed on a single element substrate 1.

In order to manufacture the electro-optical device 100 of thisembodiment, as shown in FIGS. 6A and 7B, in a first wafer preparationprocess, a first wafer 10 is prepared in which the mirrors 50 or theterminals 17 are formed for each area where the element substrate 1 isdivided, with respect to a one-side surface 10 s (a first surface) ofthe large-size first wafer 10 from which a large number of elementsubstrates 1 can be taken, and the drive element 30 (refer to FIGS. 2Ato 3B) driving each of the mirrors 50 is formed at a position whichoverlaps the mirror 50 when viewed in a plan view. For example, as shownin FIGS. 6A, 7A, and 7B, the first wafer 10 may be prepared by formingthe mirrors 50 for each area where the element substrate 1 is divided,with respect to the one-side surface 10 s of the large-size first wafer10 from which a large number of element substrates 1 can be taken, andforming the drive element 30 (refer to FIGS. 2A to 3B) driving each ofthe mirrors 50, at a position which overlaps the mirror 50 when viewedin a plan view.

Further, as shown in FIG. 6A, in a laminated wafer formation process, alaminated wafer 70 is formed in which a second wafer 20 having alight-transmitting property and a third wafer 80 having alight-transmitting property are laminated with the spacer 78 interposedtherebetween and a concave portion 21 is formed in a second surface 20 son the side opposite to the surface facing the third wafer 80, of thesecond wafer 20.

Here, in the laminated wafer formation process, for example, as shown inFIGS. 8A and 8B, the spacers 78 are formed integrally with thelarge-size third wafer 80 from which a large number of secondlight-transmitting plates 77 can be taken. Further, as shown in FIG. 8C,a fourth wafer 40 (refer to FIG. 8D) having a light-transmittingproperty, which configures the third surface 20 t side on the sideopposite to the second surface 20 s of the second wafer 20, is bonded tooverlap the side on which the spacers 78 are formed, of the third wafer80, and a fifth wafer 60 (refer to FIGS. 8C and 8F) having alight-transmitting property, which configures the second surface 20 sside of the second wafer 20, is bonded to overlap the fourth wafer 40,and thus the laminated wafer 70 is configured. Here, a through-hole 66for configuring the concave portion 21 is formed in the fifth wafer 60by etching or the like (refer to FIG. 8F). An opening on one side of thethrough-hole 66 is blocked by the fourth wafer 40, whereby thethrough-hole 66 becomes the concave portion 21. In this embodiment,after the fourth wafer 40 is bonded to overlap the third wafer 80, thefifth wafer 60 is bonded to overlap the fourth wafer 40. However, aconfiguration may be made in which after the fifth wafer 60 is bonded tooverlap the fourth wafer 40, the third wafer 80 is bonded to overlap thefifth wafer 60.

Next, in a bonding process shown in FIG. 6B, the one-side surface 10 sof the first wafer 10 and the second surface 20 s of the second wafer 20are bonded to overlap each other such that the concave portion 21overlaps the mirrors 50 when viewed in a plan view.

Next, in a dividing process shown in FIGS. 6C and 6D, a laminated body130 of the first wafer 10 and the laminated wafer 70 is divided intoportions, in each of which the cover 75 is fixed to overlap the elementsubstrate 1 provided with the mirrors 50, thereby obtaining laminatedbodies 100 s having a single item size.

In such a dividing process, first, in a second wafer dicing processshown in FIG. 6C, the laminated wafer 70 is diced by making a secondwafer dicing blade 82 penetrate from the third wafer 80 side into thelaminated wafer 70. As a result, the laminated wafer 70 is divided andthus the cover 75 is configured. At this time, the frame section 61 isconfigured by a frame portion divided from the fifth wafer 60, the firstlight-transmitting plate 76 is configured by a flat plate portiondivided from the fourth wafer 40, and the second light-transmittingplate 77 is configured by a flat plate portion divided from the thirdwafer 80.

Next, in a first wafer dicing process shown in FIG. 6D, the first wafer10 is diced by making a first wafer dicing blade 81 penetrate from thelaminated wafer 70 side into a cutting place of the laminated wafer 70with respect to the first wafer 10. As a result, a plurality of thelaminated bodies 100 s, in each of which the one-side surface is of theelement substrate 1 with the plurality of mirrors 50 formed thereon issealed by the frame section 61 and the cover 75, are manufactured.Further, in this embodiment, a wafer of a circular shape is used.However, the planar shape thereof may be a rectangular shape or thelike.

In order to perform sealing using the support substrate 90 and thesealing resin 98 shown in FIGS. 5A and 5B on the laminated body 100 sobtained by the above process, processes shown in FIGS. 9A to 9C areperformed.

First, after the support substrate 90 in which the substrate mountingportion 93 is a concave portion surrounded by the side wall 92 isprepared, as shown in FIG. 9A, the element substrate 1 is fixed to abottom portion of the substrate mounting portion 93 by the adhesive 97,as shown in FIG. 9B. Next, as shown in FIG. 9C, the terminal 17 of theelement substrate 1 and the internal electrode 94 of the supportsubstrate 90 are electrically connected to each other by the wire 99 forwire bonding. Next, as shown in FIGS. 5A and 5B, after the sealing resin98 is injected inside the side wall 92 of the support substrate 90, thesealing resin 98 is cured, whereby the element substrate 1 is sealed bythe sealing resin 98. As a result, it is possible to obtain theelectro-optical device 100 in which the element substrate 1 is sealed bythe frame section 61, the cover 75, the support substrate 90, and thesealing resin 98.

EMBODIMENT 2

FIG. 10 is a plan view of an electro-optical device 100 according toEmbodiment 2 of the invention. FIGS. 11A and 11B are cross-sectionalviews of the electro-optical device 100 according to Embodiment 2 of theinvention, in which FIG. 11A is a cross-sectional view taken along lineA2-A2′ of FIG. 10 and FIG. 11B is a cross-sectional view taken alongline B2-B2′ of FIG. 10. In addition, a basic configuration of thisembodiment is the same as that of Embodiment 1 described with referenceto FIGS. 4, 5A, 5B, and the like, and therefore, common portions aredenoted by the same reference numerals and description thereof isomitted.

In the electro-optical device 100 shown in FIGS. 10, 11A, and 11B, allof the support substrate 90, the element substrate 1, and the cover 75have a rectangular planar shape. Therefore, in the followingdescription, a description will be made regarding a direction in which ashort side in a rectangular planar shape extends, as a first directionY2, and regarding a direction in which along side extends, as a seconddirection X2.

Also in the electro-optical device 100 of this embodiment, similar toEmbodiment 1, the cover 75 has the first light-transmitting plate 76which faces the mirrors 50 from the side opposite to the elementsubstrate 1, and the second light-transmitting plate 77 which faces thefirst light-transmitting plate 76 on the side opposite to the mirrors50. Further, the cover 75 has the spacer 78 between the firstlight-transmitting plate 76 and the second light-transmitting plate 77.Here, the spacer 78 is provided at a position which does not overlap themirrors 50 when viewed in a plan view, and the gap 79 is configuredbetween the first light-transmitting plate 76 and the secondlight-transmitting plate 77 due to the spacer 78. The spacer 78 iscomposed of a convex portion formed integrally with the secondlight-transmitting plate 77.

Here, in Embodiment 1, the gap 79 is open toward an extending directionof the long side of the cover 75. However, in this embodiment, the gap79 is open toward an extending direction of the short side of the cover75. More specifically, the spacer 78 includes a first spacer 781extending in the first direction Y2, and a second spacer 782 extendingin the first direction Y2 at a position separated from the first spacer781 in the second direction X2 with respect to the first spacer 781. Forthis reason, the gap 79 is open toward both sides in the first directionY2 between the first spacer 781 and the second spacer 782. Further, theelectro-optical device 100 is provided with the blower 190 whichsupplies air toward the gap 79 from one side Y2 a in the first directionY2 with respect to the gap 79. Also in a case of being configured inthis manner, the same effect as that in Embodiment 1, such as heatdissipation in the cover 75 being able to be increased by passing afluid such as air through the gap 79, is exhibited.

EMBODIMENT 3

FIG. 12 is a cross-sectional view of an electro-optical device 100according to Embodiment 3 of the invention. In addition, a basicconfiguration of this embodiment is the same as the configurationdescribed with reference to FIGS. 4, 5A, 5B, and the like, andtherefore, common portions are denoted by the same reference numeralsand description thereof is omitted.

In the embodiment described with reference to FIGS. 4, 5A, 5B, and thelike, the height of the side wall 92 formed at the support substrate 90is the same height in any location. In contrast, in this embodiment, asshown in FIG. 12, the height from the bottom plate portion 91, of afirst side wall 921 which is located on the one side X1 a in the firstdirection X1, from which an air flow (an arrow C) is supplied, of theside wall 92, is higher the height from the bottom plate portion 91, ofa second side wall 922 which is located on the side (the other side X1 bin the first direction X1) opposite to the side from which the air flow(the arrow C) is supplied.

For this reason, as shown by the arrow C in FIG. 12, the air flow havinggotten over the first side wall 921 greatly wraps around to the insideof the first side wall 921 and then easily flows toward the gap 79.Therefore, it is possible to increase heat dissipation in the cover 75.Such a configuration may be applied to the embodiment described withreference to FIGS. 10, 11A, and 11B.

OTHER EMBODIMENTS

In the embodiments described above, the spacers 78 are disposed alongtwo sides facing each other. However, an aspect in which the spacers 78are disposed at four corner of a quadrangle may be adopted.

In the embodiments described above, the blower 190 is provided in theelectro-optical device 100. However, in FIG. 4 or 10, an electro-opticalunit is configured with an electro-optical device in which the elementsubstrate 1 and the like are supported on the support substrate 90, andthe blower 190, and in such an electro-optical unit, a structure inwhich the electro-optical device in which the element substrate 1 andthe like are supported on the support substrate 90, and the blower 190are held by the holder 180 is also acceptable. The electro-optical unithaving such a configuration is used to be fixed to a casing or the likeof the projection type display device 1000 shown in FIG. 1.

Further, in the embodiments described above, the spacer 78 is formedintegrally with the second light-transmitting plate 77. However, aconfiguration in which the spacer 78 is formed integrally with the firstlight-transmitting plate 76 may be adopted. Further, the spacer 78 maybe a separate body from the second light-transmitting plate 77 and thefirst light-transmitting plate 76, and such a configuration can berealized by making another wafer to form the spacer 78 be bonded tooverlap the third wafer 80.

What is claimed is:
 1. An electro-optical device comprising: an elementsubstrate on which a mirror and a drive element which drives the mirrorare provided on a first surface side; and a cover which is provided onthe first surface side and disposed such that the mirror is locatedbetween the element substrate and the cover, wherein the cover includesa first light-transmitting plate having a light-transmitting property, asecond light-transmitting plate having a light-transmitting property anddisposed such that the first light-transmitting plate is located betweenthe mirror and the second light-transmitting plate, and a spacer whichis interposed between the first light-transmitting plate and the secondlight-transmitting plate and provided with a gap which is open towardboth sides in a first direction intersecting a thickness direction inwhich the first light-transmitting plate and the secondlight-transmitting plate face each other, between the firstlight-transmitting plate and the second light-transmitting plate.
 2. Theelectro-optical device according to claim 1, wherein the spacer isconfigured integrally with the second light-transmitting plate.
 3. Theelectro-optical device according to claim 1, wherein the spacer includesa first spacer which extends in the first direction, and a second spacerwhich extends in the first direction at a position separated from thefirst spacer in a second direction intersecting the thickness directionand the first direction with respect to the first spacer, and the gap isopen toward both sides in the first direction between the first spacerand the second spacer.
 4. The electro-optical device according to claim3, wherein the first spacer and the second spacer extend in the firstdirection along end portions which are located on both sides in thesecond direction in the first light-transmitting plate.
 5. Theelectro-optical device according to claim 1, further comprising: ablower which supplies air toward the gap from one side in the firstdirection with respect to the gap.
 6. The electro-optical deviceaccording to claim 5, further comprising: a support substrate on whichthe element substrate is mounted, wherein the support substrate isprovided with a bottom plate portion on which the element substrate ismounted, a first side wall which protrudes from the bottom plate portionto a side on which the element substrate is mounted, on the one side inthe first direction with respect to the element substrate, and a secondside wall which protrudes from the bottom plate portion to the side onwhich the element substrate is mounted, on the other side in the firstdirection with respect to the element substrate, and the first side wallhas a higher height from the bottom plate portion than the second sidewall.
 7. An electro-optical device comprising: an element substrate onwhich a mirror and a drive element which drives the mirror are providedon a first surface side; and a cover which is provided on the firstsurface side and disposed such that the mirror is located between theelement substrate and the cover, wherein the cover includes a firstlight-transmitting plate having a light-transmitting property, a secondlight-transmitting plate having a light-transmitting property anddisposed such that the first light-transmitting plate is located betweenthe mirror and the second light-transmitting plate, and a spacer whichis located between the first light-transmitting plate and the secondlight-transmitting plate, has a first spacer extending in a firstdirection, and a second spacer extending in the first direction at aposition separated from the first spacer in a second directionintersecting the first direction with respect to the first spacer, andis provided to avoid at least a portion of a first end portion of thefirst light-transmitting plate in the first direction and avoid at leasta portion of a second end portion facing the first end portion of thefirst light-transmitting plate in the first direction.
 8. Anelectro-optical unit comprising: an electro-optical device; a blowerwhich supplies air to the electro-optical device; and a holder whichsupports the electro-optical device and the blower, wherein theelectro-optical device has an element substrate on which a mirror and adrive element which drives the mirror are provided on a first surfaceside, and a cover which is disposed such that the mirror is locatedbetween the element substrate and the cover, and the cover includes afirst light-transmitting plate having a light-transmitting property, asecond light-transmitting plate having a light-transmitting property anddisposed such that the first light-transmitting plate is located betweenthe mirror and the second light-transmitting plate, and a spacer whichis interposed between the first light-transmitting plate and the secondlight-transmitting plate at a position which does not overlap the mirrorwhen viewed in a plan view, and is provided with a gap which is opentoward both sides in a first direction intersecting a thicknessdirection in which the first light-transmitting plate and the secondlight-transmitting plate face each other, between the firstlight-transmitting plate and the second light-transmitting plate.
 9. Anelectronic apparatus comprising: the electro-optical device according toclaim 1; and a light source unit which irradiates the mirror with lightsource light.